Kapton® B Polyimide Coil

Kapton® B is DuPont's opaque black polyimide film. It shares the same base polyimide chemistry and full property profile as Kapton® HN — including the −269 °C to +400 °C thermal range, radiation resistance, and UL 94 V-0 flame rating — but the carbon-black pigmentation that gives it its distinctive black colour simultaneously blocks visible and near-infrared light, absorbs stray radiation, and reduces surface reflectivity. Unlike an applied surface coating, the opacity is homogeneous throughout the film thickness and cannot be abraded or delaminated during assembly or service. It is not a conductive grade — volume resistivity is higher than standard HN.

The carbon-black pigmentation of Kapton® B provides effective light blocking from the UV through the visible and into the near-infrared spectrum. This makes it appropriate as an optical baffle, stray-light shield, and sensor encapsulant wherever photosensitive components must be protected from ambient illumination — photodetectors, ambient light sensors, proximity sensors, and image arrays that would false-trigger or saturate in the presence of stray light.

Applied black coatings — paint, ink, or vacuum-deposited films — can outgas, flake, or delaminate in cleanroom, vacuum, and thermally cycling environments. In Kapton® B the black colouration is homogeneous throughout the film, so abrasion, flexing, or thermal cycling that removes surface material does not expose a transparent substrate beneath. For optical instruments, vacuum assemblies, and cryogenic systems where contamination from loose particles or outgassing species is unacceptable, Kapton® B's inherent opacity is the correct solution.

Kapton® B's carbon pigmentation contributes to absorption of electromagnetic radiation in the infrared and microwave spectrum, which is useful in antenna near-field suppression and flexible EMI absorber stacks where a conformal, flexible, thermally stable absorber is needed. However, it is not a conductive shielding material — for applications requiring a metallic-conductivity EMI shield, metallised Kapton® HN or the 200RS100 grade is more appropriate. Kapton® B's EMI role is absorption rather than reflection-based shielding.

Kapton® B retains the full Kapton® family thermal range — −269 °C to +400 °C continuous service — maintaining its optical opacity, dielectric integrity, and mechanical strength throughout. This qualifies it for space optical systems where cryogenic stability down to −269 °C is required alongside stray-light baffling, and for high-temperature masking and industrial applications at the upper end of the range.

Kapton® B is used in optical sensor packaging and photodetection shielding where stray light must be excluded without painted coatings; space optical instruments and cryogenic spectrometers where a flexible stray-light baffle with cryogenic stability, low outgassing, and radiation resistance is required; flexible PCB cover-lay and back-plane applications where opacity eliminates visual transmission of circuit traces; flexible electromagnetic absorber stacks for near-field EMI mitigation in handheld devices and NFC assemblies; high-temperature industrial masking where black surface absorption of radiant heat improves uniformity across thermal spray, soldering, and powder coating operations; and aerospace and defence optical baffles in electro-optical sensor systems where low reflectivity, radiation hardness, and thermal stability are simultaneously required.

Yes. Because the opacity is inherent to the film rather than applied, Kapton® B does not shed opaque particles or outgas colouring agents — a key advantage over black-painted or inked films in cleanroom and vacuum environments. It maintains its properties and opacity in ultra-high vacuum without introducing contamination from surface layers.

Kapton® B is electrically insulating. Its volume resistivity is actually higher than standard HN — the carbon black pigmentation, at the loading used, does not provide significant surface or bulk conductivity. It is not interchangeable with the 200RS100 grade, which has a resistive carbon surface coating designed for ESD dissipation and has a defined surface resistivity. Choose 200RS100 for ESD and EMI dissipation; choose B for optical opacity and light blocking.

Kapton® B responds to the same processing methods as standard HN — die-cutting, laser machining, laminating, and metallising. For optical and photonics applications where clean edge geometry around apertures is critical, laser cutting is the preferred processing method as it produces minimal heat-affected zone and burr-free edges. The film can be used as a flex circuit cover-lay and is compatible with standard PCB processing chemistry.